Cement is one of the most important and highly used building materials in the world, being is used in materials such as concrete, mortar, stucco, and many non-specialty grouts. Cement production is highly energy intensive, as a temperature of about 1450° C. is required for the process. The primary fuel used in making cement is coal, with about 120 kg of coal required per ton of cement produced. It has been estimated that about 5% of global carbon dioxide emissions originate from cement production, 50% of which is from the chemical process and 40% of which is from burning fuel. The use of coal as fuel releases to the atmosphere carbon that was sequestered underground, producing a net positive gain of carbon to the earth's atmosphere.
Fuel derived from biomass is renewable and is carbon neutral: the same amount of CO2 is removed from the atmosphere during growth of the biomass as is released to the atmosphere upon burning. Thus in contrast to coal, a biomass or biomass-derived fuel does not increase the atmospheric CO2 burden and so is more environmentally friendly.
A number of waste materials have been used as alternative fuels in cement production such as asphalt, plastics, rubber, petcoke, tires, and waste oils. In addition, agricultural and non-agricultural biomass has been suggested for use as fuel in cement production.
There remains a need for a cement kiln fueling process that makes use of a fuel that is renewable and more environmentally friendly than coal, as well as being consistent and reliable.